Aortic valve stenosis and coronary artery disease: pathophysiological and clinical links

Bibliometric analysis of treatment modalities in calcific aortic valve stenosis

Background

Calcific aortic valve stenosis (CAVS) is a common cardiovascular condition associated with significant adverse events and high mortality rates. Unfortunately, there are currently no effective pharmacological treatments to halt or prevent its progression. Through our analysis of global trends and treatment strategies, we have identified valuable insights and promising therapeutic possibilities. Additionally, by utilizing bibliometric and visualization techniques, we provide a comprehensive overview of the current research landscape in this field.

Method

According to our design idea, we used the Web of Science database to select publications on aortic stenosis and related treatments. Through our VOSviewer and CiteSpace analysis, a total of 787 articles have been analyzed by September 2024. We also summarize and explore the most prolific authors, the most prolific countries, and the journals and institutions that publish the most articles.

Results

A visual analysis of the collected articles reveals that Canada and the United States have the highest publication volumes in this field. Among institutions, Harvard University in the U.S. leads in publication count, followed by Laval University in Canada and the University of California in the U.S. The top three research hotspots are stenosis, calcification, and progression. The journal with the highest number of publications in this area is Frontiers in Cardiovascular Medicine, followed by Catheterization and Cardiovascular Interventions and Arteriosclerosis, Thrombosis and Vascular Biology. Furthermore, research on CAVS treatment spans various directions and focuses, including therapeutic approaches, pathogenesis, and diagnostic methods.

Conclusion

Research into CAVS treatment has advanced significantly over the years. While interventional and surgical valve replacement remains the mainstay treatments for aortic stenosis, they are insufficient to fully meet the needs of the patient. Emerging priorities now focus on improving diagnostics, exploring innovative therapies, uncovering disease mechanisms, and developing novel drugs. These findings highlight the evolving demands in this field and underscore the need for continued research to address these challenges.

An endogenous inhibitor of angiogenesis downregulated by hypoxia in human aortic valve stenosis promotes disease pathogenesis

Aortic valve stenosis is the most common valve disease in the western world. Central to the pathogenesis of this disease is the growth of new blood vessels (angiogenesis) within the aortic valve allowing infiltration of immune cells and development of intra-valve inflammation. Identifying the cellular mediators involved in this angiogenesis is important as this may reveal new therapeutic targets which could ultimately prevent the progression of aortic valve stenosis. Aortic valves from patients undergoing surgery for aortic valve replacement or dilation of the aortic arch were examined both ex vivo and in vitro. We now demonstrate that the anti-angiogenic protein, soluble fms-like tyrosine kinase 1 (sFlt1), a non-signalling soluble receptor for vascular endothelial growth factor, is constitutively expressed in non-diseased valves. sFlt-1 expression was, however, significantly reduced in aortic valve tissue from patients with aortic valve stenosis while protein markers of hypoxia were simultaneously increased. Exposure of primary-cultured valve interstitial cells to hypoxia resulted in a decrease in the expression of sFlt-1. We further reveal using a bioassay that siRNA knock-down of sFlt1 in valve interstitial cells directly results in a pro-angiogenic environment. Finally, incubation of aortic valves with sphingosine 1-phosphate, a bioactive lipid-mediator, increased sFlt-1 expression and inhibited angiogenesis within valve tissue. In conclusion, this study demonstrates that sFlt1 expression is directly correlated with angiogenesis in aortic valves and the observed decrease in sFlt-1 expression in aortic valve stenosis could increase valve inflammation, promoting disease progression. This could be a viable therapeutic target in treating this disease.

Sex-Related Signaling of Aldosterone/Mineralocorticoid Receptor Pathway in Calcific Aortic Stenosis

BACKGROUND

There are sex differences in the pathophysiology of aortic valve (AV) calcification in patients with aortic stenosis, although the molecular and cellular mechanisms have not been elucidated. Aldosterone (Aldo) promotes proteoglycan synthesis in valve interstitial cells (VICs) from mitral valves via the mineralocorticoid receptor (MR). We investigated the influence of sex in the role of Aldo/MR pathway in AV alterations in patients with aortic stenosis.

METHODS AND RESULTS

MR was expressed by primary aortic VICs and in AVs from patients with aortic stenosis. MR expression positively correlated with VIC activation markers in AVs from both sexes. However, MR expression was positively associated with molecules involved in AV calcification only in AV from men. Aldo enhanced VIC activation markers in cells from men and women. Interestingly, Aldo increased the expression of calcification markers only in VICs isolated from men. In female VICs, Aldo enhanced fibrotic molecules. MR antagonism (spironolactone) blocked all the above effects. Cytokine arrays showed ICAM (intercellular adhesion molecule)-1 and osteopontin to be specifically increased by Aldo in male VICs. In AVs from men, MR expression positively associated with both ICAM-1 (intercellular adhesion molecule-1) and osteopontin. Only in female VICs, estradiol treatment blocked Aldo-induced VICs activation, inflammation, and fibrosis.

CONCLUSIONS

These findings demonstrate that the Aldo/MR pathway could play a role in early stages of aortic stenosis by promoting VICs activation, fibrosis, and ulterior calcification. Importantly, Aldo/MR pathway is involved in fibrosis in women and in early AV calcification only in men. Accordingly, MR antagonism emerges as a new sex-specific pharmacological treatment to prevent AV alterations.

VLA4-Enhanced Allogeneic Endothelial Progenitor Cell-Based Therapy Preserves the Aortic Valve Function in a Mouse Model of Dyslipidemia and Diabetes

The number and function of endothelial progenitor cells (EPCs) are reduced in diabetes, contributing to deteriorated vascular repair and the occurrence of cardiovascular complications. Here, we present the results of treating early diabetic dyslipidemic mice or dyslipidemic with disease-matched EPCs modified to overexpress VLA4 (VLA4-EPCs) as compared with the treatment of EPCs transfected with GFP (GFP-EPCs) as well as EPCs from healthy animals. Organ imaging of injected PKH26-stained cells showed little pulmonary first-pass effects and distribution in highly vascularized organs, with splenic removal from circulation, mostly in non-diabetic animals. Plasma measurements showed pronounced dyslipidemia in all animals and glycaemia indicative of diabetes in streptozotocin-injected animals. Echocardiographic measurements performed 3 days after the treatment showed significantly improved aortic valve function in animals treated with VLA4-overexpressing EPCs compared with GFP-EPCs, and similar results in the groups treated with healthy EPCs and VLA4-EPCs. Immunohistochemical analyses revealed active inflammation and remodelling in all groups but different profiles, with higher MMP9 and lower P-selectin levels in GFP-EPCs, treated animals. In conclusion, our experiments show that genetically modified allogeneic EPCs might be a safe treatment option, with bioavailability in the desired target compartments and the ability to preserve aortic valve function in dyslipidemia and diabetes.

Parathyroid Hormone Induces Human Valvular Endothelial Cells Dysfunction That Impacts the Osteogenic Phenotype of Valvular Interstitial Cells

Parathyroid hormone (PTH) is a key regulator of calcium, phosphate and vitamin D metabolism. Although it has been reported that aortic valve calcification was positively associated with PTH, the pathophysiological mechanisms and the direct effects of PTH on human valvular cells remain unclear. Here we investigated if PTH induces human valvular endothelial cells (VEC) dysfunction that in turn could impact the switch of valvular interstitial cells (VIC) to an osteoblastic phenotype. Human VEC exposed to PTH were analyzed by qPCR, western blot, Seahorse, ELISA and immunofluorescence. Our results showed that exposure of VEC to PTH affects VEC metabolism and functions, modifications that were accompanied by the activation of p38MAPK and ERK1/2 signaling pathways and by an increased expression of osteogenic molecules (BMP-2, BSP, osteocalcin and Runx2). The impact of dysfunctional VEC on VIC was investigated by exposure of VIC to VEC secretome, and the results showed that VIC upregulate molecules associated with osteogenesis (BMP-2/4, osteocalcin and TGF-β1) and downregulate collagen I and III. In summary, our data show that PTH induces VEC dysfunction, which further stimulates VIC to differentiate into a pro-osteogenic pathological phenotype related to the calcification process. These findings shed light on the mechanisms by which PTH participates in valve calcification pathology and suggests that PTH and the treatment of hyperparathyroidism represent a therapeutic strategy to reduce valvular calcification.

The need for future coronary access following surgical or transcatheter aortic valve replacement

The aim of the study was to estimate the percentage of Medicare patients needing coronary access for percutaneous coronary intervention (PCI) or coronary angiography following aortic valve replacement (AVR). Indications for TAVR have expanded to include younger and low-risk patients, raising the question of coronary access for future procedures. Medicare patients <80 years old with an AVR between 2011 and 2018 were included. Time-to-event analyses were conducted using Cox hazard models to estimate risk of coronary access up to 7 years after AVR. Model adjustments included age, sex, race, region, comorbidity, concomitant CABG, and smoking. A total of 13,469 Medicare patients (mean age 70.6) met inclusion criteria. Models estimated that 2.5% of patients at 1-year post-index and 17% at over 7 years would need coronary access. For patients who had SAVR (with or without CABG), estimates for coronary access were similar and over 15% after 6.5 years. For TAVR patients, with a previous PCI, 28% at 4.5 years required coronary access, which was higher than TAVR patients without a previous PCI. SAVR patients with and without CAD at baseline were similar; however, TAVR patients with CAD had a 22% rate of coronary access versus 7% for those without at 3 years. Approximately half of patients who needed coronary access returned to the same hospital as their initial AVR. Coronary access is required in a substantial portion of AVR patients especially those with PCI or a history of CAD undergoing TAVR. The need for coronary access may increase as transcatheter AVR becomes accessible to younger patients with a longer life expectancy.

Clinical Relevance of Plasma Endogenous Tissue-Plasminogen Activator and Aortic Valve Sclerosis: Performance as a Diagnostic Biomarker

Background: Aortic valve sclerosis (AVSc), a common precursor to calcific aortic valve disease, may progress into advanced aortic stenosis with hemodynamic instability. However, plasma biomarkers of such a subclinical condition remain lacking. Since impaired fibrinolysis featuring dysregulated tissue plasminogen activator (t-PA) is involved in several cardiovascular diseases, we investigated whether endogenous t-PA was also associated with AVSc.

Methods: Plasma t-PA levels were measured in 295 consecutive patients undergoing standard echocardiography and Doppler flow imaging. Multiple logistic regression analyses were used to assess the association between t-PA and AVSc. Receiver operating characteristic curve analysis was performed for determining the diagnostic value of t-PA for AVSc. The performance of adding t-PA to clinical signatures of AVSc was evaluated. Concentration of t-PA was assessed in human sclerotic and non-sclerotic aortic valves by histology and immunohistochemistry analysis.

Results: Plasma t-PA was higher in patients with AVSc than in non-AVSc counterparts (median, 2063.10 vs. 1403.17 pg/mL, p < 0.01). C-statistics of plasma t-PA for discriminating AVSc was 0.698 (95%CI: 0.639–0.758). The performance of t-PA for identifying AVSc was better among male and non-hypertensive patients [C-statistics (95%CI): 0.712 (0.634–0.790) and 0.805 (0.693–0.916), respectively]. Combination of t-PA and clinical factors improved classification of the patients (category-free NRI: 0.452, p < 0.001; IDI: 0.020, p = 0.012). The concentration of t-PA was three times higher in sclerotic compared to non-sclerotic aortic valves.

Conclusion: Elevated circulating t-PA level confers an increased risk for AVSc. Further prospective studies with larger sample size are needed to examine if t-PA could serve as a diagnostic clinical marker for AVSc.

Vascular and valvular calcification biomarkers

Vascular and valvular calcification constitutes a major health problem with serious clinical consequences. It is important for medical laboratorians to improve their knowledge on this topic and to know which biological markers may have a potential interest and might be useful for diagnosis and for management of ectopic calcifications. This review focuses on the pathophysiological mechanisms of vascular and valvular calcification, with emphasis on the mechanisms that are different for the two types of events, which underscore the need for differentiated healthcare, and explain different response to therapy. Available imaging and scoring tools used to assess both vascular and valvular calcification, together with the more studied and reliable biological markers emerging in this field (e.g., Fetuin A and matrix Gla protein), are discussed. Recently proposed functional assays, measuring the propensity of human serum to calcify, appear promising for vascular calcification assessment and are described. Further advancement through omic technologies and statistical tools is also reported. Clinical chemistry and laboratory medicine practitioners overlook this new era that will engage them in the near future, where a close cooperation of professionals with different competencies, including laboratorists, is required. This innovative approach may truly revolutionize practice of laboratory and of whole medicine attitude, making progression in knowledge of pathways relevant to health, as the complex calcification-related pathways, and adding value to patient care, through a precision medicine strategy.

Clinical impact of low-radiation computed tomography coronary angiography diagnosis for coronary artery stenosis: Study Protocol

BACKGROUND

The objective of this study aims to assess the clinic impact of low-radiation computed tomography coronary angiography (LR-CTCA) diagnosis for coronary artery stenosis (CAS).

METHODS

This study will comprehensively search the following electronic databases from inception to the present: PUBMED, EMBASE, Cochrane Library, PsycINFO, Web of Science, Google, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, VIP database, WANGFANG, and China National Knowledge Infrastructure. All these electronic databases will be searched without language restrictions. All case-controlled studies on assessing the clinical impact of LR-CTCA diagnosis for patients with CAS will be included. Quality Assessment of Diagnostic Accuracy Studies tool will be utilized to evaluate the methodological quality for each qualified studies.

RESULTS

We will assess the clinic impact of LR-CTCA diagnosis for CAS by measuring sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio.

CONCLUSION

The results of this study will summarize the latest evidence of LR-CTCA diagnosis for CAS.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019139336.

Association of Depression With Mortality in Older Adults Undergoing Transcatheter or Surgical Aortic Valve Replacement

Importance

Depression is increasingly recognized as a risk factor for adverse outcomes in cardiovascular disease. However, little is known about depression in older adults undergoing transcatheter (TAVR) or surgical (SAVR) aortic valve replacement.

Objective

To determine the prevalence of depression and its association with all-cause mortality in older adults undergoing TAVR or SAVR.

Design, Setting, and Participants

This preplanned analysis of the Frailty Aortic Valve Replacement (FRAILTY-AVR) prospective cohort study included 14 centers in 3 countries from November 15, 2011, through April 7, 2016. Individuals 70 years or older who underwent TAVR or SAVR were enrolled. Depressive symptoms were evaluated using the Geriatric Depression Scale Short Form at baseline and follow-up.

Main Outcomes and Measures

All-cause mortality at 1 and 12 months after TAVR or SAVR. Logistic regression was used to determine the association of depression with mortality after adjusting for confounders such as frailty and cognitive impairment.

Results

Among 1035 older adults (427 men [41.3%] and 608 women [58.7%]) with a mean (SD) age of 81.4 (6.1) years, 326 (31.5%) had a positive result of screening for depression, whereas only 89 (8.6%) had depression documented in their clinical record. After adjusting for clinical and geriatric confounders, baseline depression was found to be associated with mortality at 1 month (odds ratio [OR], 2.20; 95% CI, 1.18-4.10) and at 12 months (OR, 1.532; 95% CI, 1.03-2.24). Persistent depression, defined as baseline depression that was still present 6 months after the procedure, was associated with a 3-fold increase in mortality at 12 months (OR, 2.98; 95% CI, 1.08-8.20).

Conclusions and Relevance

One in 3 older adults undergoing TAVR or SAVR had depressive symptoms at baseline and a higher risk of short-term and midterm mortality. Patients with persistent depressive symptoms at follow-up had the highest risk of mortality.

Impact of Oxidative Stress and Protein S-Glutathionylation in Aortic Valve Sclerosis Patients with Overt Atherosclerosis

Aortic valve sclerosis (AVSc) is characterized by non-uniform thickening of the leaflets without hemodynamic changes. Endothelial dysfunction, also caused by dysregulation of glutathione homeostasis expressed as ratio between its reduced (GSH) and its oxidised form (GSSG), could represent one of the pathogenic triggers of AVSc. We prospectively enrolled 58 patients with overt atherosclerosis and requiring coronary artery bypass grafting (CABG). The incidence of AVSc in the studied population was 50%. The two groups (No-AVSc and AVSc) had similar clinical characteristics. Pre-operatively, AVSc group showed significantly lower GSH/GSSG ratio than No-AVSc group (p = 0.02). Asymmetric dimethylarginine (ADMA) concentration was significantly higher in AVSc patients compared to No-AVSc patients (p < 0.0001). Explanted sclerotic aortic valves presented a significantly increased protein glutathionylation (Pr-SSG) than No-AVSc ones (p = 0.01). In vitro, inhibition of glutathione reductase caused β-actin glutathionylation, activation of histone 2AX, upregulation of α2 smooth muscle actin (ACTA2), downregulation of platelet and endothelial cell adhesion molecule 1 (PECAM1) and cadherin 5 (CDH5). In this study, we showed for the first time that the dysregulation of glutathione homeostasis is associated with AVSc. We found that Pr-SSG is increased in AVSc leaflets and it could lead to EndMT via DNA damage. Further studies are warranted to elucidate the causal role of Pr-SSG in aortic valve degeneration.

Graded murine wire-induced aortic valve stenosis model mimics human functional and morphological disease phenotype

Aortic valve stenosis (AS) is the most common valve disease requiring therapeutic intervention. Even though the incidence of AS has been continuously rising and AS is associated with significant morbidity and mortality, to date, no medical treatments have been identified that can modify disease progression. This unmet medical need is likely attributed to an incomplete understanding of the molecular mechanism driving disease development. To investigate the pathophysiology leading to AS, reliable and reproducible animal models that mimic human pathophysiology are needed. We have tested and expanded the protocols of a wire-injury induced AS mouse model. For this model, coronary wires were used to apply shear stress to the aortic valve cusps with increasing intensity. These protocols allowed distinction of mild, moderate and severe wire-injury. Upon moderate or severe injury, AS developed with a significant increase in aortic valve peak blood flow velocity. While moderate injury promoted solitary AS, severe-injury induced mixed aortic valve disease with concomitant mild to moderate aortic regurgitation. The changes in aortic valve function were reflected by dilation and hypertrophy of the left ventricle, as well as a decreased left ventricular ejection fraction. Histological analysis revealed the classic hallmarks of human disease with aortic valve thickening, increased macrophage infiltration, fibrosis and calcification. This new mouse model of AS promotes functional and morphological changes similar to moderate and severe human AS. It can be used to investigate the pathomechanisms contributing to AS development and to test novel therapeutic strategies.

I-κB kinase-ε knockout protects against angiotensin II induced aortic valve thickening in apolipoprotein E deficient mice

Aortic stenosis (AS) is considered to be an actively regulated progress that involves similar pathophysiological processes as atherosclerosis. I-κB kinase-ε (IKKε) is a proinflammatory molecule involved in atherosclerosis. The objective of the present study was to define the role of IKKε in pathological valvular remodeling. Aortic valves (AVs) from 52 patients undergoing AV replacement (AS) and 13 patients undergoing heart transplant (Control) were analyzed. ApoE^-/- mice (AK, n = 20) and ApoE^-/-IKKε^-/- mice (DK, n = 20) were generated and infused with saline or Ang II for 4 weeks. We found an upregulation of IKKε in human stenotic aortic valves compared to that in control AVs. Our results demonstrated that AK mice receiving AngII exhibited more advanced valvular remodeling and markedly increased IKKε expression. Conversely, loss of IKKε reduced adverse aortic valve thickening in response to Ang II, as measured by histological analyses. Furthermore, according to immunofluorescence analysis, Ang II resulted in obvious increases in the expression of α-SMA, TGF-β and NF-κB pathway components in the AK group, especially in the thickened area, while these increases were blocked in the DK group. Moreover, IKKε was co-expressed with α-SMA in valvular interstitial cells in ApoE^-/- mice after an AngII infusion. These data provide evidence that IKKε plays a key role in the development of valvular remodeling and that it may be a novel target for the treatment of AS.

Aspirin suppresses TNF-α-induced MMP-9 expression via NF-κB and MAPK signaling pathways in RAW264.7 cells

Numerous studies have indicated that the expression of matrix metalloproteinase-9 (MMP-9) contributes to the atherosclerotic plaque hemorrhage and rupture. Aspirin, a non-steroidal anti-inflammation drug, has been known for its anti-platelet effect in the prevention of the vascular complications of atherosclerosis. The present study aimed to investigate the pharmacological effects of aspirin on tumor necrosis factor-α (TNF-α)-induced MMP-9 expression and the underlying molecular mechanisms in murine macrophage RAW264.7 cells. Western blot analysis indicated that the protein level of MMP-9 was reduced by aspirin in a dose-dependent manner. In addition, downregulation of MMP-9 mRNA and activity were detected in aspirin-treated cells using quantitative polymerase chain reaction and a gelatin zymography assay separately. It was also observed that aspirin has a suppressive effect on the activation of nuclear factor (NF)-κB and inhibits the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinases 1/2, p38 and c-Jun N-terminal kinase. Furthermore, subsequent to inhibition of the MAPK pathway by specific inhibitors (PD98059, SB203580 and SP600125), the expression of MMP-9 was reduced, indicating that the inhibitory effect of aspirin on MMP-9 in TNF-α-treated RAW264.7 cells may be, at least in part, through suppression of NF-κB activation and the MAPK pathway. These findings support the notion that aspirin has therapeutic potential application in the prevention and treatment of atherosclerosis disease.

Aortic valve sclerosis is associated with the extent of coronaryartery disease in stable coronary artery disease

BACKGROUND/AIM

Aortic valve sclerosis (AVS) is characterized by lipid deposition and calcific infiltration on the edge of aortic leaflets without significant restriction of motion. The SYNTAX Score (SS) is an important method for evaluating coronary artery disease (CAD). Many studies showed that there is an important relation between the SS and undesired cardiac outcomes. In our study, we investigated the correlation between the SS and AVS by including both ACS and stable CAD cases.

MATERIALS AND METHODS

We enrolled 543 patients with CAD who underwent coronary angiography into this cross-sectional study between September 2013 and September 2014.

RESULTS

The study population was divided into two groups according to SS values above and below 22. Diabetes mellitus (DM) incidence was greater in the group with high SS values (26.3% vs. 19.2%, P = 0.052.). Left ventricular ejection fraction (LVEF) and glomerular filtration rate were lower. Low-density lipoprotein cholesterol and triglyceride levels were lower while platelet counts were higher. In multivariate analysis, for the stable coronary artery group AVS existence, platelet count, LVEF value, and chronic obstructive pulmonary disease were found as independent predictors.

CONCLUSION

Our study results demonstrated that AVS is significantly associated with the complexity of CAD, especially in patients with stable CAD. This study provides new information regarding the role of AVS in CAD complexity.

Aortic valve sclerosis as a marker of atherosclerosis: Novel insights from hepatic steatosis

BACKGROUND

Nowadays, aortic valve sclerosis (AVSc) might be considered an atherosclerosis-like process due to significant association with age, male gender and some major features of metabolic syndrome. Nonalcoholic fatty liver disease (NAFLD) has been recognized as a clinical expression of the metabolic syndrome and as a predictor of cardiovascular events. We aim, with this meta-analysis, to evaluate the correlation between NAFLD and AVSc; this finding might suggest new insights and interactions among NAFLD, AVSc and the atherosclerotic process.

METHODS AND RESULTS

A detailed search was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines to identify all studies providing data about the association between AVSc and NAFLD. 3 studies enrolling a total of 1172 patients with NAFLD and 1467 controls without NAFLD were included in the meta-analysis. The prevalence of AVSc was 41.3% (95% CI: 32.0%, 51.4%) in NAFLD patients and 24.6% (18.4%, 32.0%) in subjects without NAFLD with a corresponding OR of 2.28 (95% CI: 1.21, 4.28, p=0.01, I(2): 77.6%, p=0.011). A meta-regression analysis showed that age, prevalence of male gender, hypertension, body mass index, and dyslipidemia were directly and significantly associated with the difference in the prevalence of AVSc between patients with NAFLD and those without.

CONCLUSIONS

In conclusion, our meta-analysis shows a significant association between NAFLD and AVSc. However, further evidence is needed to validate these findings and find out if there is a real link or just a mere association.

Values of osteoprotegerin in aortic valve tissue in patients with significant aortic stenosis depend on the existence of concomitant coronary artery disease

INTRODUCTION

Calcific aortic valve stenosis (CAVS) is a serious clinical problem. The strongest predictor of CAVS progression is the amount of calcium in the aortic valve. The pathogenesis of CAVS is largely consistent with the pathogenesis of atherosclerosis; however, about 50% of patients with CAVS do not exhibit significant atherosclerosis. Cardiovascular calcification is currently considered an actively regulated process, in which the important role is attributed to the RANKL/RANK/OPG (receptor activator of nuclear factor κB ligand/RANK/osteoprotegerin) axis. We measured OPG levels in the tissue of calcified, stenotic aortic valves in relation to the presence or absence of coronary artery disease (CAD).

MATERIALS AND METHODS

Aortic valve samples were collected from 105 patients with calcified, mainly severe aortic stenosis, who were divided into two groups according to the presence of CAD. In Group A (n=44), there were normal coronary artery findings, while in Group B (n=61), there was angiographically demonstrated >50% stenosis of at least one coronary artery. The control Group C (n=21) consisted of patients without aortic stenosis and with normal angiographic findings on coronary arteries.

RESULTS

The highest tissue concentrations of OPG [median (pmol/L), 25th-75th percentile] were found in Group A [6.95, 3.96-18.37], which was significantly different compared to the other two groups (P=.026 and .001, respectively). The levels of OPG in Group B [4.15, 2.47-9.16] and in Group C [2.25, 1.01-5.08] did not differ significantly (P=.078); however, the lowest concentrations of OPG were found in Group C. Neither age nor gender in our study had effect on tissue levels of OPG (P=.994 for gender; P=.848 for age).

CONCLUSION

Calcified and narrowed aortic valves, compared to the normal valves, were accompanied by a change in tissue concentrations of OPG, which is, in addition, dependent on the presence or absence of CAD. The highest tissue concentrations of OPG in our work were found in patients with significant aortic stenosis without concomitant CAD.

Development of Aortic Valve Disease in Familial Hypercholesterolemic Swine: Implications for Elucidating Disease Etiology

Background

Familial hypercholesterolemia (FH) is a prevalent hereditary disease associated with increased atherosclerosis and calcific aortic valve disease (CAVD). However, in both FH and non‐FH individuals, the role of hypercholesterolemia in the development of CAVD is poorly understood. This study used Rapacz FH (RFH) swine, an established model of human FH, to investigate the role of hypercholesterolemia alone in the initiation and progression of CAVD. The valves of RFH swine have not previously been examined.

Methods and Results

Aortic valve leaflets were isolated from wild‐type (0.25‐ and 1‐year‐old) and RFH (0.25‐, 1‐, 2‐, and 3‐year‐old) swine. Adult RFH animals exhibited numerous hallmarks of early CAVD. Significant leaflet thickening was found in adult RFH swine, accompanied by extensive extracellular matrix remodeling, including proteoglycan enrichment, collagen disorganization, and elastin fragmentation. Increased lipid oxidation and infiltration of macrophages were also evident in adult RFH swine. Intracardiac echocardiography revealed mild aortic valve sclerosis in some of the adult RFH animals, but unimpaired valve function. Microarray analysis of valves from adult versus juvenile RFH animals revealed significant upregulation of inflammation‐related genes, as well as several commonalities with atherosclerosis and overlap with human CAVD.

Conclusions

Adult RFH swine exhibited several hallmarks of early human CAVD, suggesting potential for these animals to help elucidate CAVD etiology in both FH and non‐FH individuals. The development of advanced atherosclerotic lesions, but only early‐stage CAVD, in RFH swine supports the hypothesis of an initial shared disease process, with additional stimulation necessary for further progression of CAVD.

High sensitivity C reactive protein as a prognostic marker in patients with mild to moderate aortic valve stenosis during lipid-lowering treatment: an SEAS substudy

AIMS

To assess the prognostic importance of high-sensitive C reactive protein (hsCRP) in patients with mild to moderate aortic valve stenosis during placebo or simvastatin/ezetimibe treatment in Simvastatin and Ezetimibe in Aortic Stenosis (SEAS).

METHODS AND RESULTS

In 1620 SEAS patients, we measured lipids and hsCRP at baseline and after 1 year of treatment and registered during 4 years of follow-up major cardiovascular events (MCE) composed of ischaemic cardiovascular events (ICE) and aortic valve-related events (AVE). Simvastatin/ezetimibe reduced low-density lipoprotein cholesterol (3.49 (2.94 to 4.15) to 1.32 (1.02 to 1.69) vs 3.46 (2.92 to 4.08) to 3.34 (2.81 to 3.92) mmol/L) and hsCRP (2.1 (0.9 to 4.1) to 1.2 (0.6 to 2.4) vs 2.2 (0.9 to 4.9) to 1.8 (0.85 to 4.35) mg/L, all p<0.05) during the first year of treatment. In multivariable Cox regression analysis adjusting for traditional risk factors and baseline hsCRP, ICE was associated with a 1-year increase of hsCRP (HR=1.19 (95% CI 1.12 to 1.25), p<0.001) but not with active treatment (HRTreatment=0.86 (0.67 to 1.13), p=0.28). Patients in the top quartile of baseline hsCRP versus the rest were associated with a higher risk of MCE (HR=1.34(1.09 to 1.64), p=0.02). The prognostic benefit of reduction in hsCRP after 1 year was significantly larger (p<0.01 for interaction) in patients with high versus low baseline hsCRP; hence, a reduction in hsCRP abolished the difference in incidence of MCE between high versus low baseline hsCRP in patients with reduced hsCRP (31.1 vs 31.9%, NS) in contrast to patients with increased hsCRP.

CONCLUSIONS

The treatment-associated reduction in ICE was in part related to a reduction in hsCRP but not in lipids. hsCRP reduction was associated with less MCE, especially in patients with high baseline hsCRP.

TRIAL REGISTRATION

NCT00092677.

Scaffolds for tissue engineering of cardiac valves

Tissue engineered heart valves offer a promising alternative for the replacement of diseased heart valves avoiding the limitations faced with currently available bioprosthetic and mechanical heart valves. In the paradigm of tissue engineering, a three-dimensional platform - the so-called scaffold - is essential for cell proliferation, growth and differentiation, as well as the ultimate generation of a functional tissue. A foundation for success in heart valve tissue engineering is a recapitulation of the complex design and diverse mechanical properties of a native valve. This article reviews technological details of the scaffolds that have been applied to date in heart valve tissue engineering research.

A Novel Mouse Model of Aortic Valve Stenosis Induced by Direct Wire Injury

Objective—

The response-to-tissue-injury theory is currently the favorite paradigm to investigate valve pathology. To the best of our knowledge, there are currently no in vivo valve injury models. There are few calcific aortic valve stenosis (AVS) models that develop hemodynamically significant stenosis. Here, we investigated the effect of direct mechanical injury on aortic valves in vivo and developed a novel mouse model of calcific AVS.

Approach and Results—

Aortic valve injury was created by inserting and moving a spring guidewire under echocardiographic guidance into the left ventricle of male C57/BL6 mice via right common carotid artery. Serial echocardiographic measurements revealed that aortic velocity was increased 1 week after injury and persistently increased until 16 weeks after injury. AVS mice showed a higher heart weight/body weight ratio and decreased left ventricular fractioning shortening 4 weeks after injury, compared with sham mice. We found remarkable proliferation of valve leaflets 4 weeks after injury. Proliferative valves showed increased production of reactive oxygen species and expression of inflammatory cytokines and osteochondrogenic factors. Alizarin red staining showed valvular calcification 12 weeks after injury.

Conclusions—

We report a novel calcific AVS model to support the response-to-tissue-injury theory. This model may be a valuable tool for analyzing the mechanism of AVS and assessing therapeutic options.

Associations between aspirin and other non-steroidal anti-inflammatory drugs and aortic valve or coronary artery calcification: the Multi-Ethnic Study of Atherosclerosis and the Heinz Nixdorf Recall Study

BACKGROUND

The association between non-steroidal anti-inflammatory drugs (NSAIDs) and the incidence of valvular and arterial calcification is not well established despite known associations between these drugs and cardiovascular events.

OBJECTIVE

To compare the association between the baseline use of aspirin with other NSAID class medications with the incidence and prevalence of aortic valve calcification (AVC) and coronary artery calcification (CAC).

METHODS

The relationship of NSAID use to AVC and CAC detected by computed tomography was assessed in 6814 participants within the Multi-Ethnic Study of Atherosclerosis (MESA) using regression modeling. Results were adjusted for age, sex, ethnicity, study site, anti-hypertensive medication use, education, income, health insurance status, diabetes, smoking, exercise, body mass index, blood pressure, serum lipids, inflammatory markers, fasting glucose, statin medication use, and a simple diet score. Medication use was assessed by medication inventory at baseline which includes the use of non-prescription NSAIDs. MESA collects information on both incident and prevalent calcification. The 4814 participants of the Heinz Nixdorf Recall (HNR) Study, a German prospective cohort study with similar measures of calcification, were included in this analysis to enable replication.

RESULTS

Mean age of the MESA participants was 62 years (51% female). After adjustment for possible confounding factors, a possible association between aspirin use and incident AVC (Relative Risk(RR): 1.60; 95%Confidence Interval (CI): 1.19-2.15) did not replicate in the HNR cohort (RR: 1.06; 95%CI: 0.87-1.28). There was no significant association between aspirin use and incident CAC in the MESA cohort (RR 1.08; 95%CI: 0.91-1.29) or in the HNR cohort (RR 1.24; 95%CI: 0.87-1.77). Non-aspirin NSAID use was not associated with either AVC or CAC in either cohort. There were no associations between regular cardiac dose aspirin and incident calcification in either cohort.

CONCLUSION

Baseline NSAID use, as assessed by medication inventory, appears to have no protective effect regarding the onset of calcification in either coronary arteries or aortic valves.

Calcific aortic valve damage as a risk factor for cardiovascular events

Aortic valve calcification (AVC) is a common disease of the elderly. It is a progressive disease ranging from mild valve thickening to severe calcification with aortic valve stenosis. Risk factors for AVC are similar to those for atherosclerosis: age, gender, hypercholesterolemia, diabetes, hypertension, smoking and renal failure. AVC shares many similarities to atherosclerosis, including inflammatory cells and calcium deposits, and correlates with coronary plaque burden. Presence of AVC is associated with increased risk of adverse cardiovascular events. The objective for this review is to discuss the clinical features, natural history and prognostic significance of aortic valve calcifications, including mechanical and hemodynamic factors of flow distribution.

Aortic valve calcification in mild primary hyperparathyroidism

CONTEXT

It is unclear whether cardiovascular disease is present in primary hyperparathyroidism (PHPT).

OBJECTIVE

Aortic valve structure and function were compared in PHPT patients and population-based controls.

DESIGN

This is a case-control study.

SETTING

The study was conducted in a university hospital metabolic bone disease unit.

PARTICIPANTS

We studied 51 patients with PHPT and 49 controls.

OUTCOME MEASURES

We measured the aortic valve calcification area and the transaortic pressure gradient.

RESULTS

Aortic valve calcification area was significantly higher in PHPT (0.24 ± 0.02 vs. 0.17 ± 0.02 cm(2), p<0.01), although there was no difference in the peak transaortic pressure gradient, a functional measure of valvular calcification (5.6 ± 0.3 vs. 6.0 ± 0.3 mm Hg, P = 0.39). Aortic valve calcification area was positively associated with PTH (r = 0.34; P < 0.05) but not with serum calcium, phosphorus, or 25-hydroxyvitamin D levels or with calcium-phosphate product. Serum PTH level remained an independent predictor of aortic valve calcification area after adjustment for age, sex, body mass index, smoking status, history of hypercholesterolemia and hypertension, and estimated glomerular filtration rate.

CONCLUSIONS

Mild PHPT is associated with subclinical aortic valve calcification. PTH, but not serum calcium concentration, predicted aortic valve calcification. PTH was a more important predictor of aortic valve calcification than well-accepted cardiovascular risk factors.

Calcific aortic valve stenosis: methods, models, and mechanisms

Calcific aortic valve stenosis (CAVS) is a major health problem facing aging societies. The identification of osteoblast-like and osteoclast-like cells in human tissue has led to a major paradigm shift in the field. CAVS was thought to be a passive, degenerative process, whereas now the progression of calcification in CAVS is considered to be actively regulated. Mechanistic studies examining the contributions of true ectopic osteogenesis, nonosseous calcification, and ectopic osteoblast-like cells (that appear to function differently from skeletal osteoblasts) to valvular dysfunction have been facilitated by the development of mouse models of CAVS. Recent studies also suggest that valvular fibrosis, as well as calcification, may play an important role in restricting cusp movement, and CAVS may be more appropriately viewed as a fibrocalcific disease. High-resolution echocardiography and magnetic resonance imaging have emerged as useful tools for testing the efficacy of pharmacological and genetic interventions in vivo. Key studies in humans and animals are reviewed that have shaped current paradigms in the field of CAVS, and suggest promising future areas for research.

In patients with aortic stenosis increased flow-mediated dilation is independently associated with higher peak jet velocity and lower asymmetric dimethylarginine levels

BACKGROUND

Recently, it has been shown that endothelial dysfunction and aortic stenosis (AS) share several risk factors. Endothelial function represents a crucial factor for the regulation of vascular tonus and its malfunction influences the formation of thrombosis and inflammation. However, the role of endothelial dysfunction in AS remains unclear.

METHODS

Echocardiographic, clinical, and laboratory data of 34 patients (age 74.5 ± 7.9 years, 20 men) with at least moderate AS (peak jet velocity 3.8 ± 0.8 m/s) were collected. In all patients, endothelial function was determined by brachial artery flow-mediated dilation (FMD). Patients with rheumatic or endocarditic valve disease, bicuspid valves, a left ventricular ejection fraction of ≤40%, and coronary artery disease were excluded. Sixteen volunteers (age 69.3 ± 9.4 years, 10 men) without valve disease served as controls.

RESULTS

Patients with AS had a trend toward a lower FMD than controls with a comparable risk profile (5.4% ± 3.6% vs 7.4% ± 4.1%, P = .1). Univariate correlates of FMD in patients with AS were peak jet velocity, medication with angiotensin-converting enzyme inhibitor, diabetes, diastolic blood pressure, and asymmetric dimethylarginine. Backward elimination identified peak jet velocity (β = 0.51, P = .001), and asymmetric dimethylarginine (β = -0.45, P = .003) as independent predictors of FMD in multivariate analysis.

CONCLUSIONS

In patients with AS, we found a strong positive relation between the peak jet velocity and a higher FMD. This effect might be mediated by nitric oxide release due to turbulent poststenotic blood flow or the rising transvalvular gradient, and the increasing pulse pressure may be counteracted by a parallel increase in FMD.